The total loop conversion efficiency used in the Solar Field is the product of the loop optical efficiency and the receiver heat loss efficiency. I understand the optical efficiency to be the absorbed power/ incident power, and the receiver heat loss efficiency would then be the (absorbed power - heat loss)/ absorbed power. But, judging by the total loop conversion efficiency result, SAM seems to calculate the heat loss efficiency as (absorbed power - heat loss)/ incident power. This does not seem correct, and would give an incorrect value for the total loop conversion efficiency. Am I mistaken?